1. Field of the Invention
The present invention relates to a DVD/CD player, and more particularly, to a combined DVD/CD data processor for use in the DVD/CD player.
2. Description of the Related Art
A DVD (Digital Video Disk) player includes optical and servo systems of which functions and structures are similar to those used in a CD (Compact Disk) player. Therefore, in order to offer convenience to a user, there has been a demand for a DVD player compatible with the CD player.
FIG. 1 illustrates a schematic block diagram of a combined DVD and CD player according to the state of the art. As illustrated, a spindle motor 12 rotates a disk 10 which is a DVD or a CD. An optical pickup 14 reads an RF (Radio Frequency) signal from the disk 10, and an RF amplifier 16 converts the RF signal read by the pickup 14 into a pulse stream, to generate an EFM (Eight to Fourteen Modulated) signal. A microprocessor 20 sets the DVD/CD player to a DVD mode or a CD mode, according to lead-in information received from the RF amplifier 16. A data processor 18 processes the EFM signal according to the set operation mode.
FIG. 2 illustrates the data processor 18 according to the prior art. In operation, the EFM signal is applied in common to a phase locked loop (hereinafter, referred to as PLL)24, a DVD data processor 26, and a CD data processor 38. The PLL 24 generates a PLL clock in synchronism with the EFM signal. The PLL clock is used for reproducing data recorded on the disk 10.
If the microprocessor 20 sets the DVD/CD player to the DVD or the CD mode according to the lead-in information, one of the DVD data processor 26 and the CD data processor 38 is selectively driven.
The DVD data processor 26 includes a frame/ID (Identification) synchronization detector 28, an EFM+ (Eight to Fourteen Modulation Plus) demodulator 30, an RS (Reed-Solomon) decoder 34, an external memory 32, and a descrambler 36. The frame/ID synchronization detector 28 detects a synchronization pattern from the EFM signal to generate a symbol clock to the EFM+ demodulator 30. The EFM+ demodulator 30 EFM+ demodulates the EFM signal according to the symbol clock, and stores the demodulated data into the external memory 32. If the demodulated data stored in the external memory 32 becomes as large as an ECC (Error Checking and Correction) block size, the RS decoder 34 reads the demodulated data with the ECC block size and RS-decodes it to correct errors of the data. The error corrected data is stored back into the external memory 32. The descrambler 36 reads the error corrected data stored in the external memory 32 to descramble the read data and provide the same to an external ATAPI (AT Attachment Packet Interface). Here, in case the DVD/CD player is set to the DVD mode, the descrambled (output) data is applied to an AV (Audio-Visual) decoder.
The CD data processor 38 includes a frame/ID synchronization detector 40, an EFM demodulator 42, an internal memory 44, a deinterleaver 46, a CIRC (Cross Interleave Reed Solomon Code) decoder 48, and an audio processor 50. The frame/ID synchronization detector 40 detects the synchronization pattern from the EFM signal to generate a symbol clock to the EFM demodulator 42. The EFM demodulator 42 EMF-demodulates the EFM signal according to the symbol clock. The demodulated data is deinterleaved by the deinterleaver 46 and stored into the internal memory 44. If the demodulated and deinterleaved data stored in the internal memory 44 reaches a predetermined size, the CIRC decoder 48 reads the demodulated data from the internal memory 44 and CIRC-decodes it to correct errors of the data. The audio processor 50 processes the error corrected data.
As described above, the conventional DVD/CD player includes the DVD data processor 26 and the CD data processor 38 separately, and drives one of them according to the set operation mode, which results into an increase of the complexity of the device, as well as the manufacturing cost.